Designing of Synoptic Patterns of Winds in the Southern Coasts of Caspian Sea (1983-85)
Abstract
Abstract
Many people know the important effects of Caspian Sea winds and storms on the economy of three provinces of Iran including Gilan, Mazandaran, and Golestan that they form one exclusive and extent area which have moderate and humid climate. This paper used a synoptic climatologically approach, which combine a number of atmospheric factors. Using daily and monthly winds data including their speed and direction for determining of 61 wind waves (1983 to 1985), and then 20 representative ones and analyzing daily air maps, 13 synoptic patterns of troughs, and polar front jet stream (PFJ) at 500 hPa level, and Siberian High is produced during the peak days of wind waves and middle days of calm periods. Results indicate that much of troughs grouped in the west of Caspian Sea during the peak days of wind waves but they were completely scattered during the middle days of calm periods. Also, the northwest-southeast direction of trough axes and FPJ location between 40 to 50°E confirmed that troughs have dominant effect for the appearing of sever winds. Finally, the schematic and tridimentional pattern of southern Caspian Sea winds as another result showed during autumn, dominant wind speed is lower than winter. This can be the principal factor of maximum rainfall during autumn in study area.
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